1. Technical Field
The present invention relates to a conductive ball mounting apparatus, a conductive ball mounting method, a mask used for mounting conductive balls, and a mask manufacturing method. More particularly, the present invention relates to a conductive ball mounting apparatus for mounting one conductive ball on each of a plurality of pads coated with an adhesive flux formed on a substrate such as a wiring substrate or a semiconductor wafer, a conductive ball mounting method, a mask used for mounting conductive balls, and a mask manufacturing method.
2. Background Art
FIG. 1 is a sectional view of a conductive ball mounting apparatus in the related art. FIG. 1 shows a conductive ball mounting apparatus 10 mounting each of conductive balls 24 on each of a plurality of pads 17 formed on a substrate 15.
By reference to FIG. 1, the conductive ball mounting apparatus 10 in the related art includes a stage 11, a conductive ball mounting mask 12, and a conductive ball supplying unit 13.
The stage 11 is configured to hold the substrate 15 having the plurality of pads 17 coated with a flux 16. The conductive ball mounting mask 12 is disposed over the substrate 15 such that the conductive ball mounting mask 12 is stretched by a certain tension in the horizontal direction (a state that the conductive ball mounting mask 12 is not caused to bend). The conductive ball mounting mask 12 has a plurality of ball mounting through holes 19 that are used to mount each of the conductive balls 24 on each of the plurality of pads 17 (pads on which the flux 16 is coated).
The conductive ball supplying unit 13 has a suction head 21, a sucking unit 22, and a driving unit 23. The suction head 21 has an inlet port 21A. The suction head 21 is disposed over the conductive ball mounting mask 12 such that the inlet port 21A opposes to the conductive ball mounting mask 12. When the sucking unit 22 is driven, the suction head 21 collects the plurality of conductive balls 24, which are supplied onto the conductive ball mounting mask 12, on a portion of the conductive ball mounting mask 12 opposing to the suction head 21.
The sucking unit 22 is provided on the suction head 21. The sucking unit 22 sucks the portion of the conductive ball mounting mask 12 opposing to the inlet port 21A (upper surface 12A side of the conductive ball mounting mask 12) via the inlet port 21A.
The driving unit 23 is provided to the suction head 21. The driving unit 23 moves the suction head 21 in the direction that is parallel with the upper surface 12A of the conductive ball mounting mask 12.
The conductive ball supplying unit 13 mounts each of the conductive balls 24 on each of the plurality of pads 17 (pads on which the flux 16 is coated) by moving the suction head 21 and the plurality of conductive balls 24 in the direction that is parallel with the upper surface 12A of the conductive ball mounting mask 12, while collecting the plurality of conductive balls 24, which are supplied onto the upper surface 12A of the conductive ball mounting mask 12, on the portion of the upper surface 12A of the conductive ball mounting mask 12 opposing to the inlet port 21A of the suction head 21 (see e.g., JP-A-2006-73999).
However, when each of the conductive balls 24 is mounted on each of the plurality of pads 17 using the conductive ball mounting mask 12 in the related art, an air flow between the upper side and the lower side of the conductive ball mounting mask 12 is worsened in respective areas where the conductive balls 24 are mounted on the pads 17, as shown in FIG. 1.
FIG. 2 is a view to describe disadvantages when each of the conductive balls is mounted on each of the pads using the conductive ball mounting apparatus in the related art. In FIG. 2, the same reference symbols are affixed to the same constituent portions as those of the structure shown in FIG. 1.
As shown in FIG. 2, in the related art method, the conductive ball mounting mask 12 is lifted up from a certain position by a sucking force generated by the conductive ball supplying unit 13. In this manner, when the conductive ball mounting mask 12 is lifted up from the certain position, other balls 24 fall through the ball mounting through holes 19 positioned over the pads 17 on which each of the conductive balls 24 is mounted. As a result, such a problem existed that the mounting position of the conductive balls 24 mounted on the pads 17 is displaced from a desired position, or such a problem existed that the plurality of conductive balls 24 are mounted on each of the pads 17.